Hi,
I can't find an answer to the following question in AS/NZS3000 so I'm hoping someone with more experience can help.
If using a 16mm² 3C+E circular TPS can the following be done.
Red Core: Feed to a 15kW charging system for LiPO4 batteries.
White Core: Sleeved Red and used as the return from a 10kVA single phase inverter
Blue Core: Sleeved Black and used as a common neutral.
Green Core: System Earth
The 10kVA inverter is phase sync'd to the feed to the charging system.
The current from the neutral will effectively be the feed current minus the return current because the voltages are in=phase but current's out of phase so the maximum neutral current would be for 15kVA charge when there is no load present.
Is a common neutral allowed in this type of system or are separate feed and return cables with their own neutrals required?
Common Neutral - Allowed??
Re: Common Neutral - Allowed??
Refer 2.2.1.3
The underlying requirement - bold typeface, so a fundamental requirement - is that every single-phase circuit must have its own N.
Common N is effectively an exception to this rule; and is only permitted for two circuits "originating from the same supply", also subject to specific conditions.
Your proposed arrangement is 2 circuits, each from a different supply.
Therefore each requires its own N.
The underlying requirement - bold typeface, so a fundamental requirement - is that every single-phase circuit must have its own N.
Common N is effectively an exception to this rule; and is only permitted for two circuits "originating from the same supply", also subject to specific conditions.
Your proposed arrangement is 2 circuits, each from a different supply.
Therefore each requires its own N.
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